This invention relates to a valve control structure for a working vehicle, and more particularly to a valve control structure in which one of two control valves is operable by a rocking movement in a first direction of a crosswise rockable control lever and the other control valve is operable by a rocking movement in a second direction of the control lever.
A known example of the above construction is found with a backhoe wherein a control valve for actuating a swivel deck and a control valve for vertically oscillating a bucket-carrying arm are operated by a single lever rockable crosswise. For this construction one of the following two operational modes is employed, i.e. a mode in which the swivel deck control valve is operated by a rocking movement of the control lever in a fore-and-aft direction of the swivel deck and the arm control valve is operated by a rocking movement of the control lever in a transverse direction of the swivel deck, or a mode in which, conversely to the above, the swivel deck control valve is operated by a rocking movement of the control lever in the transverse direction of the swivel deck and the arm control valve is operated by a rocking movement of the control lever in the fore-and-aft direction of the swivel deck.
Therefore, when a working vehicle is borrowed or is provided new, the vehicle may have an operational mode different from the mode to which the operator is accustomed. In such a situation the operator is prone to a danger of operational error such as actuating the arm when the swivel deck should be actuated.
Furthermore, with certain types of backhoe implement, a bucket-carrying arm is adapted to move at an accelerated speed and the acceleration is effected by switching of hydraulic lines extending between control valves and actuators. However, such a construction has the inconvenience that the hydraulic line switching causes an actuator which has been accelerable to become no longer accelerable and the other actuator to become accelerable.